Study On Soil Contamination Characteristics And Environmental Risks Of Key Industrial Sites In Heavy Industrial Zone Of Northeast China

The protection of soil environment is important to maintain national ecological security and promote the construction of ecological civilization.As an important old industrial base in China,Northeast China has been promoting the transformation of Northeast China’s industrial structure in recent years with the national strategy of Northeast China’s revitalization,leaving behind a number of polluted sites with long history of pollution and complex pollution status.It is an urgent environmental and social problem to study the types,sources,composition and pollution pathways of soil pollutants and assess the risks of the sites.In this paper,contaminated sites in three typical industries(petrochemical,machinery manufacturing and non-ferrous smelting)in the northeastern heavy industrial zone are studied,and their pollution characteristics,pollution causes and environmental risks are systematically investigated by jointly applying various techniques,with the following main results:The results of pollutants and pollution characteristics identification show that the petrochemical site pollution status is the most complex,there are many types of composite pollution,petrochemical and non-ferrous smelting industries respectively with runoff and rainfall dripping as the main pollution pathway,machinery manufacturing industry there are other pollution pathways.PAHs,VOCs and TPH pollution status petrochemical > machinery manufacturing > non-ferrous smelting,the main pollution factors are Bb F,Ba P,Dah A,TPH(C10-C40),CT,CF,BEN;heavy metal pollution status non-ferrous smelting > machinery manufacturing > petrochemical,the main pollution factors are Cr,Cd,Pb,Ni,Hg.PAHs,VOCs and TPH exceeds the standard multiplier increases with depth,and heavy metal exceeds the standard multiplier decreases with depth;PAHs,VOCs and TPH exceed the standard most seriously in the petrochemical industry,whose main pollutants exceed the standard are Bb F,Ba P,Dah A and TPH(C10-C40),CT,CF,TCP,BEN,ΜCB,CM,non-ferrous smelting industry Heavy metal exceeds the most serious,its main exceeded pollutants are Cr,Hg.machinery manufacturing industry pollution depth is deeper,the overall trend for non-ferrous smelting > machinery manufacturing > petrochemical.The results of pollution source analysis show that the pollution sources of the petrochemical industry are chemical reaction production sources,traffic sources,oil and coal storage sources;the pollution sources of the machinery manufacturing industry are machining sources,metal surface treatment sources,coal storage sources and metal welding sources;the pollution sources of the non-ferrous smelting industry are smelting sources,raw materials and fuel storage sources.The results of human health risk and ecological environment evaluation of contaminants in soil show that the potential ecological risk of PAHs at three types of industrial sites is petrochemical > machinery manufacturing > non-ferrous smelting in order of magnitude.The potential ecological risk indices of heavy metals in the three industries are in the order of non-ferrous smelting > machinery manufacturing >petrochemicals,and the main risk factors are Cd and Hg.The potential ecological risk size of VOCs in three types of industries is petrochemical > machinery manufacturing >non-ferrous smelting in order,and the main risk factor is PXL.The average total carcinogenic risk for both adults and children was in the order of non-ferrous smelting >petrochemical > machinery manufacturing,and the total average carcinogenic risk for children in machinery manufacturing sites was in the acceptable range,while the rest were in the unacceptable level.For the three to focus on the carcinogenic risk of the industry sites should focus on Ba P,Dah A,Cr,As,CT,TCE,EDC,BEN.The total average non-carcinogenic risk to adults and children is in the order of non-ferrous smelting > machinery manufacturing > petrochemicals,and the total average noncarcinogenic risk of contaminants in soil at all three types of sites is in the unacceptable range.For the three to focus on the non-carcinogenic risk of industry sites should focus on Nap,Pb,Hg,DCM,BEN,GX,TCE,TCE,BEN.The results of parameter sensitivity analysis showed that BW was the main negative influencing factor.For heavy metals,DAIR had the greatest effect on carcinogenic risk,OSIR,AF,ABS were the main influencing factors for non-carcinogenic risk;the overall sensitivity of parameters for carcinogenic risk and non-carcinogenic risk of VOCs was consistent,OSIR,BW,AF,ABS were the main influencing factors;the trend of parameter sensitivity for carcinogenic risk of PAHs was BW > AF > OSIR > ABS > DAIR > EF > SA,noncarcinogenic risk AF and ABS were the main influencing factors.The analysis of the pollution characteristics of the three key industries in the northeast heavy industrial zone and the results of the risk assessment show that the petrochemical industry generally has a high content of pollutants,the most complex pollution situation and the most sources of pollution,but the risk of pollutants in the soil of the non-ferrous smelting industry is higher than that of the other two types of industries,which should be monitored and treated with emphasis on the main source areas of these two types of industries in order to reduce the impact on the ecological environment.